REGULATION OF AMINO-ACID-TRANSPORT IN THE RENAL EPITHELIAL-CELL LINE NBL-1

The activities of the transport systems A, B degrees and X(AG)- are in duced by various forms of stress in renal epithelial cells. Amino acid deprivation induces System A and X(AG)- in a protein-synthesis depend ent process. In the case of System X(AG)- evidence is presented that i nduction of transport does not involve an increase in the amount of mR NA for the transporter or of the amount of transport protein. Prelimin ary evidence for the existence of a novel glycoprotein which is induce d in parallel to the induction of these transport systems is presented . It is suggested that the induction of amino acid transport proteins and of some of the so-called stress proteins may be triggered by a com mon molecular mechanism.